Detection of occult tumor cells in lymph nodes from non-small cell lung cancer patients using reverse transcription-polymerase chain reaction for carcinoembryonic antigen mRNA with the evaluation of its sensitivity

NUF2 Expression in Cancer Tissues and Lymph Nodes Suggests Post-Surgery Recurrence of Non-Small Cell Lung Cancer

In non-small cell lung cancer (NSCLC) cases, detecting potential lymph node metastases is essential to determine the indications for sublobar resection or adjuvant therapy. NUF2 is a tumor-specific antigen that is highly expressed in lung cancer tissues. However, the significance of analyzing NUF2 expression in dissected lymph nodes has not yet been studied. Thus, we investigated the association between NUF2 expression in lung cancer tissues and dissected lymph nodes and early recurrence of NSCLC to determine its usefulness as a marker of lymph node micrometastasis. This retrospective study quantified NUF2 expression in the cancer tissues of 88 patients with NSCLC who underwent complete resection using real-time polymerase chain reaction and investigated its relationship with clinicopathological features and prognosis. We also quantified NUF2 RNA expression in mediastinal lymph nodes from 255 patients with pN0 NSCLC who underwent complete resection with lymph node dissection and analyzed its association with prognosis. NUF2 expression in primary tumors was correlated with lymph node metastasis and unfavorable outcomes in terms of poor recurrence-free and cancer-specific survival. In N0 NSCLC cases, high NUF2 expression in mediastinal lymph nodes indicated poor prognosis, especially in lymph node recurrence. NUF2 emerges as a promising marker for predicting lymph node metastatic recurrence, offering potential utility in guiding post-surgical adjuvant therapy for lung cancer or assisting in intraoperative decisions for sublobar resection.

Combination of CEACAM5, EpCAM and CK19 gene expressions in mediastinal lymph node micrometastasis is a prognostic factor for non-small cell lung cancer

BACKGROUND

Lung cancer is known as the most common and highly metastatic form of cancer worldwide. Tumour node metastasis (TNM) staging is the gold standard classification system for the decision-making process for appropriate treatment. Particularly N status has the most important prognostic value in the absence of distant metastasis. Traditional diagnostic methods are capable of detecting metastasis; however, they may fail to detect micrometastasis, which plays a role in disease recurrence and patients' long-term survival. Occult micrometastasis can change the tumour's TNM staging and, consequently, the patient's treatment regimen.

METHODS

The median number of three lymph node tissues were collected from 30 patients who underwent surgery for non-small cell lung cancer. Lymph node tissues were collected from different lymph node stations according to the location of the patient's tumour. CK19, EpCAM and CEACAM5 gene expressions were analysed in tissues using quantitative real-time polymerase chain reaction to detect micrometastasis in distant lymph nodes.

RESULTS

Triple positivity was seen in 26 out of 30 patients which 19 patients were upstaged from N0 to N2. While survival was not significantly affected between upstaged and non-upstaged patients, patients upstaged with multiple-station N2 had a significantly higher recurrence and lower survival compared to single-station N2.

CONCLUSION

A combination of CK19, EpCAM and CEACAM5 gene expressions in lymph nodes can be used to identify micrometastasis which postoperatively may be used as a tool to predict patients' recurrence and survival.

Clinical Significance of Molecular Micrometastasis in the Sentinel Lymph Node of Early-stage Non-Small Cell Lung Cancer Patients

OBJECTIVES

Metastatic affectation of lymph node is the main prognostic factor in localized lung cancer. A pathologic study of the obtained samples, even after adequate lymphadenectomy, showed tumor relapses for 20% of stage I patients after oncological curative surgery. We evaluated the prognostic value of molecular micrometastasis in the sentinel lymph node of patients with early-stage lung cancer.

PATIENTS AND METHODS

The sentinel node was marked immediately after performing thoracotomy by peritumorally injecting 0.25 mCi of nanocoloid of albumin (Nanocol1) labeled with Tc-99m in 0.3 mL. Guided by a Navigator1 gammagraphic sensor, we proceeded to its resection. The RNA of the tissue was extracted, and the presence of genes CEACAM5, BPIFA1, and CK7 in mRNA was studied. The significant association between the presence of micrometastasis, clinicopathologic characteristics, and patients' outcome was assessed.

RESULTS

Eighty-nine stage I-II non-small cell lung cancer patients were included in the study. Of the 89 analyzed sentinel lymph nodes, 44 (49.4%) were positive for CK7, 24 (26.9%) for CEACAM5, and 17 (19.1%) for BPIFA1, whereas 10 (11.2%) were positive for the 3 analyzed genes. A survival analysis showed no significant relation between the presence of molecular micrometastasis in the sentinel node and patients' progression.

CONCLUSIONS

The molecular analysis of the sentinel node in patients with early-stage lung cancer shows node affectation in cases staged as stage I/II by hematoxylin-eosin or an immunohistochemical analysis. However, this nodal affectation was not apparently related to patients' outcome.

Detection of disseminated tumor cells in lymph nodes from patients with early stage non-small cell lung cancer

BACKGROUND

The regional lymph node involvement is a major prognostic factor in patients with non-small cell lung cancer (NSCLC) undergoing surgical resection. Disease relapse is common, suggesting that early disseminated disease is already present in the regional lymph nodes at the time of surgery, and that the current nodal staging classification might be suboptimal. Early detection of disseminated tumor cells (DTCs) in lymph nodes could potentially enable identification of subcategories of patients with high risk of disease relapse.

METHOD

Lymph node samples were collected from 128 NSCLC patients at the time of surgery and the presence of DTCs determined by immunomagnetic selection (IMS) using the MOC31 antibody recognizing EpCAM. Results obtained with IMS were compared to the pathological staging obtained by histopathology. Associations between the presence of DTCs and clinicopathological variables and patient outcome were investigated.

RESULTS

DTCs were detected in 40 % of the lymph node samples by IMS. Their presence was significantly associated with pN status as assessed by histopathology, and samples from 83 % of the patients with lymph node metastases (pN1-2) had detectable DTCs. In the group of patients who were negative for lymph node metastases by standard histopathology (pN0) DTCs were detected in 32 %. The presence of DTCs was not associated with any other clinicopathological variables. Patients with IMS-positive samples showed decreased relapse free survival compared to patients with IMS-negative samples, but the difference was not statistically significant. The pN status was significantly associated with both relapse free and overall survival, but the presence of DTCs had no prognostic impact in the subcategory of patients with pN0 status.

CONCLUSION

Our findings do not support further development of lymph node DTC detection for clinical use in early stage NSCLC.

Current innovations in sentinel lymph node mapping for the staging and treatment of resectable lung cancer

Despite surgical resectability, early-stage lung cancer remains a challenge to cure. Survival outcomes are hindered by variable performance of adequate lymphadenectomy and the limitations of current pathologic nodal staging. Sentinel lymph node (SLN) mapping, a mainstay in the management of breast cancer and melanoma, permits targeted nodal sampling for efficient and accurate staging that can influence both intraoperative and adjuvant treatment decisions. Unfortunately, standard SLN identification techniques with blue dye and radiocolloid tracers have not been shown to be reproducible in lung cancer. In more recent years, intraoperative near-infrared image-guided lung SLN mapping has emerged as promising technology for the identification of the tumor-associated lymph nodes most likely to contain metastatic disease. Additionally, the clinical relevance of SLN mapping for lung cancer remains pressing, as the ability to identify micrometastatic disease in SLNs could facilitate trials to assess chemotherapeutic response and the clinical effect of occult nodal disease. This review outlines the status of lung cancer lymphatic mapping and techniques in development that may help close the gap between translational research in this field and routine clinical practice.

Lymph node micrometastases detected by carcinoembryonic antigen mRNA affect long-term survival and disease-free interval in early-stage lung cancer patients

The majority of stage I lung cancer patients undergo a complete resection of their tumor; however, they still harbor a considerable risk of mortality due to recurrences. A correlation between the presence of lymph node micrometastases and poor prognosis has been observed. The aim of this study was to correlate the lymph node molecular staging with the 5-year survival and disease-free interval following pulmonary lobectomy for non-small cell lung cancer (NSCLC). A quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for carcinoembryonic antigen (CEA) mRNA was performed on primary lung tumors and regional lymph nodes from 55 surgically resected NSCLC patients classified as clinical stage I. CEA mRNA was found to be present in all the primary tumors. RT-PCR revealed the presence of cancer cells in the lymph nodes of 20 patients (36.3%) and routine staining detected lymph node metastases in 11 patients. Significant differences in survival and disease-free intervals were observed in patients with lymph node micrometastases versus patients with negative lymph nodes (P=0.0026 and P=0.0044, respectively). Multivariate analyses confirmed that micrometastases were an independent predictor for worse prognosis (P=0.0098) and a short disease-free interval (P=0.0137). This study demonstrated strong correlations between the molecular detection of lymph node micrometastases and 5-year survival rates and disease-free interval in patients who underwent pulmonary lobectomy for early-stage lung cancer.

Contralateral mediastinal lymph node micrometastases assessed by video-assisted thoracoscopic surgery in stage I non-small cell left lung cancer

OBJECTIVES

Survival of patients with left-sided stage I non-small cell lung cancer (NSCLC) is unsatisfactory, probably because of the high incidence of contralateral mediastinal node involvement. In this study, occult micrometastases to the right upper mediastinal nodes were retrospectively investigated in patients with left-sided stage I NSCLC.

METHODS

Nineteen patients with clinical stage I NSCLC underwent video-assisted thoracoscopic lobectomy and bilateral mediastinal node dissection (BMD). Clinical data and survival of patients with BMD were compared with those of 25 left-unilateral mediastinal node dissection (UMD) patients. Occult micrometastases were detected using the cytokeratin 19 mRNA reverse transcription-polymerase chain reaction method.

RESULTS

Pathological N2 disease was found in 1 patient, and 18 had pN0 disease. The operative time, blood loss, duration of chest tube drainage and duration of postoperative hospital stay were not different between BMD and UMD patients. Nodal micrometastases were detected in 11/19 (57.8%) patients. Skip micrometastases to the level N3 nodes without N1 and N2 node involvement were observed in 8/11 (72.7%) patients. Patients with BMD are all alive and have had no recurrence during the median follow-up period of 21.4 months. Overall 3-year survival and disease-free 3-year survival were not significantly different between the two groups.

CONCLUSION

In this preliminary study, occult micrometastases to the level N3 nodes occurred frequently in patients with left-sided clinical N0 stage I NSCLC. Postoperative survival of patients with occult micrometastases to the level N3 node does not appear to be poor. Further follow-up and work are needed.

Occult metastases in lymph nodes predict survival in resectable non-small-cell lung cancer: report of the ACOSOG Z0040 trial

PURPOSE

The survival of patients with non-small-cell lung cancer (NSCLC), even when resectable, remains poor. Several small studies suggest that occult metastases (OMs) in pleura, bone marrow (BM), or lymph nodes (LNs) are present in early-stage NSCLC and are associated with a poor outcome. We investigated the prevalence of OMs in resectable NSCLC and their relationship with survival.

PATIENTS AND METHODS

Eligible patients had previously untreated, potentially resectable NSCLC. Saline lavage of the pleural space, performed before and after pulmonary resection, was examined cytologically. Rib BM and all histologically negative LNs (N0) were examined for OM, diagnosed by cytokeratin immunohistochemistry (IHC). Survival probabilities were estimated using the Kaplan-Meier method. The log-rank test and Cox proportional hazards regression model were used to compare survival of groups of patients. P < .05 was considered significant.

RESULTS

From July 1999 to March 2004, 1,047 eligible patients (538 men and 509 women; median age, 67.2 years) were entered onto the study, of whom 50% had adenocarcinoma and 66% had stage I NSCLC. Pleural lavage was cytologically positive in only 29 patients. OMs were identified in 66 (8.0%) of 821 BM specimens and 130 (22.4%) of 580 LN specimens. In univariate and multivariable analyses OMs in LN but not BM were associated with significantly worse disease-free survival (hazard ratio [HR], 1.50; P = .031) and overall survival (HR, 1.58; P = .009).

CONCLUSION

In early-stage NSCLC, LN OMs detected by IHC identify patients with a worse prognosis. Future clinical trials should test the role of IHC in identifying patients for adjuvant therapy.

A pragmatic approach to the diagnosis of nodal micrometastases in early stage non-small cell lung cancer

INTRODUCTION

This study was designed to develop a both sensitive and efficient algorithm for detection of lymph node micrometastases and to determine its prognostic impact in patients with early stage non-small cell lung cancer (NSCLC).

METHODS

One hundred seventy patients with NSCLC p stage I and II were included in this study, of which n = 5299 lymph nodes were obtained and submitted to histopathologic analysis. From each patient, a median number of 31 lymph nodes was received (N-1 position: median n = 16; N-2 position: median n = 15). Immunohistochemistry was performed to detect micrometastases unobvious by conventional microscopy using antibodies against cytokeratins (CK) (pan-CK: KL-1, CK 5/6, CK 7) and the epithelial marker Ber-EP4.

RESULTS

In 82 patients (48.2%), micrometastases were revealed in immunohistochemistry staining. KL-1 detected micrometastases in 201 (99.5%) of 202 positive lymph nodes. Subsequently, this resulted in an upstaging in 39 patients (20.5%). Detection of micrometastases in otherwise tumor-free N2-lymph nodes had a significant prognostic impact (mean disease-free survival 21.4 versus 45.3 months, p = 0.022), affecting 4.7% of patients. Survival differences between patients who were upstaged into stage II (N0>N1) and those remaining in stage I were not statistically significant (p = 0.537).

CONCLUSION

Extended workup of N2-lymph nodes using one broad-spectrum keratin marker in otherwise N2-negative lymph nodes may represent a both efficient and sensitive approach to the identification of micrometastases in dissected lymph nodes of patients with early stage NSCLC.

Quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR) in translational oncology: lung cancer perspective

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) is rapidly becoming a basic method in lung cancer research. Analysis of transcriptional activity of tumor cells or detection of tumor markers by this technique has the potential to change lung cancer diagnosis and treatment. Quantitative RT-PCR is characterized by unparalleled sensitivity and specificity, with very reliable reproducibility. Its prime advantage for gene expression analysis is its broad dynamic range of 10(7)-fold. Moreover, it is cost-effective, feasible in every day laboratory routine and efficient in terms of biological material consumption. Still, there are a number of methodological aspects that need to be carefully considered before it can sensibly be implemented into clinical practice. Three major technical issues: the choice of chemistries, gene expression data normalization and statistical processing of the results will be specifically highlighted in this review. Further, clinical applications of qRT-PCR will be thoroughly discussed: detection and staging of lung cancer and construction and validation of prognostic and predictive gene expression signatures.

Circulating tumor cells in peripheral blood caused by surgical manipulation of non-small-cell lung cancer: pilot study using an immunocytology method

OBJECTIVE

Reverse transcriptase-polymerase chain reaction assay results have indicated that tumor cells sometimes appear during surgery for primary non-small-cell lung cancer. In this study, we attempted to determine whether cancer cells can be detected during and after surgery using an immunocytology method.

METHODS

Nine patients undergoing a lobectomy for non-small-cell lung cancer were studied. The presence of circulating tumor cells was determined by the detection of magnified EpCAM antibodies. The criteria used to identify circulating tumor cells were a round-to-oval morphology with a visible nucleus (4'-6'-diamidino-2-phenylindole (DAPI)-positive), which were positive for cytokeratin and negative for CD45.

RESULTS

One patient showed evidence of circulating tumor cells at thoracotomy, and 3 patients did so after surgery. Ten days after the operation, the circulating tumor cells had disappeared in all these cases. The median follow-up period was 14 months, and there was no cancer recurrence in any of the patients.

CONCLUSION

Using this technique, tumor cells were detected in the peripheral blood of patients before and after lobectomy procedures. It could be argued that this method can provide useful information about patients undergoing lung cancer treatment.